Remove unnecessary audio references in PeerConnectionFactory
We currently pass in a lot of audio parameters to PeerConnectionFactory
which we never use. This CL removes them.
All these parameters are reference counted, so they are not needed for
lifetime management (unless we do something crazy). Even if we want to
switch from reference counting to std::unique_ptrs in the future, the
voice engine is a more suitable owner than PeerConnectionFactory. The
PeerConnectionFactory already owns a MediaEngine which in turn owns a
VoiceEngine.
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